Definition of Aortic dissection:

Aortic dissection is a potentially life-threatening condition in which there is bleeding into and along the wall of the aorta, the major artery carrying blood out of the heart.

Causes, incidence, and risk factors:

When it leaves the heart, the aorta first moves up through the chest toward the head (the ascending aorta). It then bends or arches, and finally moves down through the chest and abdomen (the descending aorta).

Aortic dissection most often occurs because of a tear or damage to the inner wall of the aorta.

This usually occurs in the thoracic (chest) portion of the artery, but may also occur in the abdominal portion.

An aortic dissection is classified as type A or B depending on where it begins and ends.

• Type A begins in the first (ascending) part of the aorta.
• Type B begins in the descending part of the aorta.

When a tear occurs, it creates two channels: One in which blood continues to travel and another where blood remains still. As the aortic dissection grows bigger, the channel with nontraveling blood can get bigger and push on other branches of the aorta.

An aortic dissection may also involve abnormal widening or ballooning of the aorta (aneurysm).

The exact cause is unknown, but risks include atherosclerosis (hardening of the arteries) and high blood pressure. Traumatic injury is a major cause of aortic dissection, especially blunt trauma to the chest. Hitting the steering wheel of a car during an accident is a common traumatic cause.

Other risk factors and conditions associated with the development of aortic dissection include:

• Aging
• Bicuspid aortic valve
• Coarctation (narrowing) of the aorta
• Connective tissue disorders
• Ehlers-Danlos syndrome
• Heart surgery or procedures
• Marfan syndrome
• Pregnancy
• Pseudoxanthoma elasticum
• Vascular inflammation due to conditions such as arteritis and syphilis

Aortic dissection occurs in approximately 2 out of every 10,000 people. It can affect anyone, but is most often seen in men aged 40 to 70.